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7 results on '"Bernard-Salas, J."'

1. Detection of C60 and C70 in a young planetary nebula.

Author

Cami J, Bernard-Salas J, Peeters E, and Malek SE

Subjects
Extraterrestrial Environment, Cosmic Dust, Fullerenes, Stars, Celestial chemistry
Abstract

In recent decades, a number of molecules and diverse dust features have been identified by astronomical observations in various environments. Most of the dust that determines the physical and chemical characteristics of the interstellar medium is formed in the outflows of asymptotic giant branch stars and is further processed when these objects become planetary nebulae. We studied the environment of Tc 1, a peculiar planetary nebula whose infrared spectrum shows emission from cold and neutral C60 and C70. The two molecules amount to a few percent of the available cosmic carbon in this region. This finding indicates that if the conditions are right, fullerenes can and do form efficiently in space.

Published
2010
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2. Probing the baryon cycle of galaxies with SPICA mid- and far-infrared observations

Author

van, der Tak F. F. S., Madden, S. C., Roelfsema, P., Armus, L., Baes, M., Bernard-Salas, J., Bolatto, A., Bontemps, S., Bot, C., Bradford, C. M., Braine, J., Ciesla, L., Clements, D., Cormier, D., Fernandez-Ontiveros, J. A., Galliano, F., Giard, M., Gomez, H., Gonzalez-Alfonso, E., Herpin, F., Johnstone, D., Jones, A., Kemper, F., Lebouteiller, V., De, Looze I., Matsuura, M., Perez-Gonzalez, P., Shipman, R., Spinoglio, L., Kaneda, Hidehiro, Nakagawa, Takao, Onaka, Takashi, Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Sterrenkundig Observatorium, Universiteit Gent, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, FORMATION STELLAIRE 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire astronomique de Strasbourg (OAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, University of Zaragoza - Universidad de Zaragoza [Zaragoza], Formation Stellaire, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, University of Manchester [Manchester], foreign laboratories (FL), CERN [Genève], Antarctic Research a European Network for Astrophysics (ARENA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Institut d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Astrophysique de Bordeaux [Pessac] ( LAB ), Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire astronomique de Strasbourg ( OAS ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Astrophysique de Marseille ( LAM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Aix Marseille Université ( AMU ) -Centre National d'Etudes Spatiales ( CNES ), Zentrum für Astronomie der Universität Heidelberg ( ZAH ), Istituto di Astrofisica e Planetologia Spaziali ( IAPS ), Istituto Nazionale di Astrofisica ( INAF ), Centre d'étude spatiale des rayonnements ( CESR ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Universidad de Zaragoza, foreign laboratories ( FL ), Antarctic Research a European Network for Astrophysics ( ARENA ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universiteit Gent = Ghent University (UGENT), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universität Heidelberg [Heidelberg] = Heidelberg University, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
C-II, [ SDU.ASTR.GA ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), FOS: Physical sciences, Spica, SPECTRAL ENERGY-DISTRIBUTIONS, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 01 natural sciences, infrared: galaxies, H-II REGIONS, CO-TO-H-2 CONVERSION FACTOR, 0103 physical sciences, STAR-FORMING GALAXIES, Astrophysics::Solar and Stellar Astrophysics, NEARBY GALAXIES, GIANT BRANCH STARS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, QB, Cosmic dust, SPITZER-SPACE-TELESCOPE, Luminous infrared galaxy, Physics, Science & Technology, extinction, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy, Astronomy and Astrophysics, DIFFUSE INTERSTELLAR-MEDIUM, Astrophysics - Astrophysics of Galaxies, Galaxy, Interstellar medium, LOW-METALLICITY GALAXIES, ISM: dust, 0201 Astronomical And Space Sciences, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), galaxies: star formation, Physical Sciences, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Earth and Planetary Astrophysics, galaxies: ISM, ISM: dust, extinction, techniques: spectroscopic
Abstract

The SPICA mid and far-infrared telescope will address fundamental issues in our understanding of star formation and ISM physics in galaxies. A particular hallmark of SPICA is the outstanding sensitivity enabled by the cold telescope, optimized detectors, and wide instantaneous bandwidth throughout the mid- and far-infrared. The spectroscopic, imaging and polarimetric observations that SPICA will be able to collect will help in clarifying the complex physical mechanisms which underlie the baryon cycle of galaxies. In particular: (i) The access to a large suite of atomic and ionic fine-structure lines for large samples of galaxies will shed light on the origin of the observed spread in star formation rates within and between galaxies. (ii) Observations of HD rotational lines (out to $\sim$10 Mpc) and fine structure lines such as [CII] 158 $\mu$m (out to $\sim$100 Mpc) will clarify the main reservoirs of interstellar matter in galaxies, including phases where CO does not emit. (iii) Far-infrared spectroscopy of dust and ice features will address uncertainties in the mass and composition of dust in galaxies, and the contributions of supernovae to the interstellar dust budget will be quantified by photometry and monitoring of supernova remnants in nearby galaxies. (iv) Observations of far-infrared cooling lines such as [OI] 63 $\mu$m from star-forming molecular clouds in our Galaxy will evaluate the importance of shocks to dissipate turbulent energy. The paper concludes with requirements for the telescope and instruments, and recommendations for the observing strategy., Comment: Accepted for publication in PASA; 19 pages, 8 figures, 1 table

Published
2017

3. AGB stars as an origin of dust and gas in the interstellar medium of galaxies.

Author

Matsuura, M., Zijlstra, A. A., Wood, P. R., Sloan, G. C., Groenewegen, M. A. T., Lagadec, E., Van Loon, J. Th., Whitelock, P. A., Bernard-Salas, J., Menzies, J. W., Cioni, M.-R. L., Feast, M. W., and Harris, G. J.

Subjects
ASYMPTOTIC giant branch stars, INTERSTELLAR medium, COSMIC dust, GALAXIES, ASTROPHYSICS
Abstract

We have obtained infrared spectra of carbon stars in four nearby galaxies—the Large and Small Magellanic Clouds, and the Fornax dwarf spheroidal galaxy. Our primary aim is to investigate mass-loss rate and gas compositions of these stars as a function of metallicity, by comparing AGB stars in several galaxies with different metallicities. These stars were observed using the Infrared Spectrometer (IRS) onboard the Spitzer Space Telescope which covers 5–35 μm region, and the Infrared Spectrometer And Array Camera (ISAAC) on the Very Large Telescope which covers the 2.9–4.1 μm region. HCN, CH and C2H2 molecular bands, as well as SiC and MgS dust features are identified in the spectra. We find no evidence that mass-loss rates depend on metallicity. Carbon stars are strongly affected by carbon production during the AGB phase; primarily mass-loss of carbon-rich stars are driven by amorphous carbon dust grains, that explains the little metallicity dependence of mass-loss rate for carbon-rich stars. We found that C2H2 bands are prominent features at 3–15 μm among extragalactic carbon stars, which is not always the case for Galactic carbon stars. We argue that carbon produced in AGB stars dominate the gas and dust chemistry in these stars in low metallicities. [ABSTRACT FROM AUTHOR]

Published
2008
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4. Physical structure of the photodissociation regions in NGC 7023.

Author

Köhler, M., Habart, E., Arab, H., Bernard-Salas, J., Ayasso, H., Abergel, A., Zavagno, A., Polehampton, E., van der Wiel, M. H. D., Naylor, D. A., Makiwa, G., Dassas, K., Joblin, C., Pilleri, P., Berné, O., Fuente, A., Gerin, M., Goicoechea, J. R., and Teyssier, D.

Subjects
PHOTODISSOCIATION, PLANETARY nebulae, FOURIER transform spectrometers, INTERSTELLAR medium, COSMIC dust
Abstract

Context. The determination of the physical conditions in molecular clouds is a key step towards our understanding of their formation and evolution of associated star formation. We investigate the density, temperature, and column density of both dust and gas in the photodissociation regions (PDRs) located at the interface between the atomic and cold molecular gas of the NGC 7023 reflection nebula. We study how young stars affect the gas and dust in their environment. Aims. Several Herschel Space Telescope programs provide a wealth of spatial and spectral information of dust and gas in the heart of PDRs. We focus our study on Spectral and Photometric Image Receiver (SPIRE) Fourier-Transform Spectrometer (FTS) fully sampled maps that allow us for the first time to study the bulk of cool/warm dust and warm molecular gas (CO) together. In particular, we investigate if these populations spatially coincide, if and how the medium is structured, and if strong density and temperature gradients occur, within the limits of the spatial resolution obtained with Herschel. Methods. The SPIRE FTS fully sampled maps at different wavelengths are analysed towards the northwest (NW) and the east (E) PDRs in NGC 7023. We study the spatial and spectral energy distribution of a wealth of intermediate rotational 12CO 4 ⩽ Ju ⩽ 13 and 13CO 5 ⩽ Ju ⩽ 10 lines. A radiative transfer code is used to assess the gas kinetic temperature, density, and column density at different positions in the cloud. The dust continuum emission including Spitzer, the Photoconductor Array Camera and Spectrometer (PACS), and SPIRE photometric and the Institute for Radio Astronomy in the Millimeter Range (IRAM) telescope data is also analysed. Using a single modified black body and a radiative transfer model, we derive the dust temperature, density, and column density. Results. The cloud is highly inhomogeneous, containing several irradiated dense structures. Excited 12CO and 13CO lines and warm dust grains localised at the edge of the dense structures reveal high column densities of warm/cool dense matter. Both tracers give a good agreement in the local density, column density, and physical extent, leading to the conclusion that they trace the same regions. The derived density profiles show a steep gradient at the cloud edge reaching a maximum gas density of 105-106 cm-3 in the PDR NGC 7023 NW and 104-105 cm-3 in the PDR NGC 7023 E and a subsequent decrease inside the cloud. Close to the PDR edges, the dust temperature (30 K and 20 K for the NW and E PDRs, respectively) is lower than the gas temperature derived from CO lines (65-130 K and 45-55 K, respectively). Further inside the cloud, the dust and gas temperatures are similar. The derived thermal pressure is about 10 times higher in NGC 7023 NW than in NGC 7023 E. Comparing the physical conditions to the positions of known young stellar object candidates in NGC 7023 NW, we find that protostars seem to be spatially correlated with the dense structures. Conclusions. Our approach combining both dust and gas delivers strong constraints on the physical conditions of the PDRs. We find dense and warm molecular gas of high column density in the PDRs. [ABSTRACT FROM AUTHOR]

Published
2014
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5. Evolution of dust in the Orion Bar with Herschel I. Radiative transfer modelling.

Author

Arab, H., Abergel, A., Habart, E., Bernard-Salas, J., Ayasso, H., Dassas, K., Martin, P. G., and White, G. J.

Subjects
COSMIC dust, ASTRONOMICAL photometry, STAR formation, INTERSTELLAR medium, PHOTODISSOCIATION
Abstract

Context. Interstellar dust is a key element in our understanding of the interstellar medium and star formation. The manner in which dust populations evolve with the excitation and the physical conditions is a first step in comprehending the evolution of interstellar dust. Aims. Within the framework of the Evolution of interstellar dust Herschel key programme, we have acquired PACS and SPIRE spectrophotometric observations of various photodissociation regions, to characterise this evolution. The aim of this paper is to trace the evolution of dust grains in the Orion Bar photodissociation region. Methods. We used Herschel/PACS (70 and 160 μm) and SPIRE (250, 350 and 500 μm) together with Spitzer/IRAC observations to map the spatial distribution of the dust populations across the Bar. Brightness profiles were modelled using the DustEM model coupled with a radiative transfer code. Results. Thanks to Herschel, we are able to probe in great detail the dust emission of the densest parts of the Orion Bar with a resolution from 5.6'' to 35.1'' . These new observations allow us to infer the temperature of the biggest grains at different positions in the Bar, which reveals a gradient from ∼70 K to 35 K coupled with an increase of the spectral emissivity index from the ionization front to the densest regions. Combining Spitzer/IRAC observations, which are sensitive to the dust emission from the surface, with Herschel maps, we were able to measure the Orion Bar emission from 3.6 to 500 μm. We find a stratification in the different dust components that can be quantitatively reproduced by a simple radiative transfer model without dust evolution (diffuse interstellar medium abundances and optical properties). However, including dust evolution is needed to explain the brightness in each band. Polycyclic aromatic hydrocarbon (PAH) abundance variations, or a combination of PAH abundance variations with an enhancement of the biggest grain emissivity caused by coagulation give good results. Another hypothesis is to consider a length of the Bar along the line of sight different at the ionization front than in the densest parts. [ABSTRACT FROM AUTHOR]

Published
2012
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6. THE RICH CIRCUMSTELLAR CHEMISTRY OF SMP LMC 11.

Author

Malek, S. E., Cami, J., and Bernard-Salas, J.

Subjects
STAR observations, NEBULA spectra, PROPENE, CIRCUMSTELLAR matter, COSMIC dust
Abstract

Carbon-rich evolved stars from the asymptotic giant branch to the planetary nebula phase are characterized by a rich and complex carbon chemistry in their circumstellar envelopes. A peculiar object is the preplanetary nebula SMP LMC 11, whose Spitzer Infrared Spectrograph spectrum shows remarkable and diverse molecular absorption bands. To study how the molecular composition in this object compares to our current understanding of circumstellar carbon chemistry, we modeled this molecular absorption. We find high abundances for a number of molecules, perhaps most notably benzene. We also confirm the presence of propyne (CH3C2H) in this spectrum. Of all the cyanopolyynes, only HC3N is evident; we can detect at best a marginal presence of HCN. From comparisons to various chemical models, we can conclude that SMP LMC 11 must have an unusual circumstellar environment (a torus rather than an outflow). [ABSTRACT FROM AUTHOR]

Published
2012
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